Arylamidase of Neisseria catarrhalis.
Neisseria catarrhalis produces arylamidase intracellularly and is one of the gram-negative bacteria producing exceptionally large amounts of this enzyme. In general, gram-positive bacteria do not produce this enzyme. Arylamidase from N. catarrhalis was purified by salt fractionation, chromatography, and density gradient ultracentrifugation. Its sedimentation coefficient was 6.6; l-alanine-beta-naphthylamide (betaNA) was the most rapidly hydrolyzed amino acid-betaNA. The enzyme had pK(e) values of 6.1 and 8.7 and pK(es) values of 7.1 and 7.9; only those amino acid-betaNA compounds of the l configuration were susceptible to hydrolysis. Arylamidase catalyzed stepwise hydrolysis of dipeptide-betaNA, beginning with the N-terminal residue. Substrates having amino acid residues with larger R groups, such as leucine, interacted much more effectively with enzyme. The significance of the predominate occurrence of arylamidase activity in gram-negative bacteria and the role of this enzyme in the physiology of these organisms remain unclear. It has been established, however, that arylamidase is distinct from leucine aminopeptidase.
D000581:Amidohydrolases; D000626:Aminopeptidases / Q000302:isolation & purification / Q000378:metabolism; D001426:Bacterial Proteins / Q000032:analysis; D002499:Centrifugation, Density Gradient; D002852:Chromatography, Ion Exchange; D002854:Chromatography, Paper; D004589:Electrophoresis, Disc; D006863:Hydrogen-Ion Concentration; D009343:Neisseria / Q000201:enzymology*; D014461:Ultracentrifugation
D001426:Bacterial Proteins; D000626:Aminopeptidases; D000581:Amidohydrolases